2006 Gulf Stream Cavalier lights flickering and dimming

[natemoore]

Hi all. Just purchased a new 30' Cavalier FEMA trailer. This one is very nice and clean, but has a couple of issues.

If I had an owners manual, I could answer some of these questions myself.

Under a 30 amp hookup, the overhead lights are very dim when they are turned on one at a time. Turn them all on and they are very bright, but they flicker on and off. One time, a certain light switch would make a smoke detector start screaming, but I never could tell where the alarm was; seemed like that piercing sound was coming from everywhere. One time, a light switch caused the a/c to turn on and off. Could not duplicate this error.

My old popup had DC lights and a converter. Does this GS trailer have a converter w/ DC lights too?

Any idea?

[natemoore]

Update.

I'm assuming that maybe some moisture was present in the electrical system because once the air conditioner was run for a few hours, all these little quirks stopped.

However, the light dimming issue is still present.

We've noticed that the lights brighten when the converter cooling fan turns on, which is counter-intuitive. You'd think that they would DIM when an additional load is added.

I thought perhaps the trailer's battery would help to smooth out the voltage fluctuations. The battery is charging (warm and bubbly), but it only measured 11.75 volts, so I'm wondering if this four year old battery needs to be replaced.

Am I the only person on this forum who has had a dimming light problem?

[DAF]

Your problem could be (from simple to expensive):

a) a bad connection at the power converter (incoming AC and DC)
b) low AC (shore) voltage
c) an overloaded power converter
d) a bad battery causing an overloaded power converter
e) a bad power converter

You mention that the battery is "warm and bubbly" @ 11.75v. That supports assumpion c & d. I would disconnect the battery and check if there are any changes. I would also measure the voltage at the positive lead without the battery. It should be a between 13 and 14 volts. Make sure all connections at the power converter are tight and that there is no discoloration at the bare copper ends. If all connections are sound and the battery voltage is within specs, I would try a known good battery, any 12v car battery will do.

Good luck!

[natemoore]

Took some measurements with my voltmeter. 121 volts at the 30 amp plug. 13.5 volts at the charging terminals for the battery. 13.5 to 14.5 volts at the circuit board lugs.

Then, with no other A/C loads, I turned on every DC light the got back to the lugs on the circuit to see what happened. When the cooling fan kicked on, the lights began to dim and I saw the voltage slowly bleed down (along with fan speed) to about 7.5 volts.

When I turned off all the lights, voltage came back up to 13.5.

Any EE's out there who can help? This thing is just a step down transformer, a rectifier, capacitor, and a voltage regulator. Most electrical components either work or don't work, but I suppose a VR could degrade.

Ideas?

[natemoore]

Well, I pulled the MBA assembly. The cooling fan looks like one from a computer power supply. I don't think it's the culprit....so......something is causing the voltage to start off withing specs (13.6V), but slowly decrease to about half that when a considerable load is applied.

Help me out, guys. The voltage regulator uses a reference voltage to maintain the output voltage; it's a negative feedback loop. Could something be causing the Vr to decrease and the output voltage is following it downward?

Where does Vr come from?

Any ideas? Anybody?

/crickets/

[DAF]

By the results of your tests, the only possibilities I can think of are a 1) a bad connection at the converter which will result in a significant voltage drop under load or 2) a bad converter. A converter board can fail all at once or can just seem to work at no load but fail to supply the rated load. Most probably you are dealing with a bad converter board.

Good luck!

[natemoore]

Well, I found a new MBA for about $150. Hey, this is kinda like owning a boat.

Thanks.

[sierra_91_2000]

you can download the owners manual at the gulfstream site. click on the travel trailer pic on the home page. then click on "contact us" when you get to that page the last thing listed is a pdf form of the manual. Its the general manual for all the 2005-2006 travel and 5th wheel trailers.

Hope this helps

[natemoore]

you can download the owners manual at the gulfstream site. click on the travel trailer pic on the home page. then click on "contact us" when you get to that page the last thing listed is a pdf form of the manual. Its the general manual for all the 2005-2006 travel and 5th wheel trailers.

Hope this helps

Thanks.

I re-soldiered the circuit board in hopes that the problem was a cold soldier joint. No luck. Installed the new converter and new battery. Lights are bright and steady.